A TEENAGER who wrote violent sexual fantasies about young girls on his computer and down-loaded indecent images of children from the internet has been given an indeterminate sentence.

In passing a sentence of imprisonment for public protection, Judge John Saunders at Birmingham Crown Court said Matthew Embrey had written his "sexual thoughts and fantasies" about young girls and what he would like to do to them.

"There is no doubt he has an obsession with girls much younger than he is," he said.

And he said he believed there was a "significant risk" that Embrey, of Tamworth, could put his fantasises into practise.

He said Embrey had also previously been convicted of indecently touching a girl as well as harassment and making threats to kill after his advances had been rejected.

Judge Saunders said other material had also been found in which he had given a "graphic description" of what he intended to do to the girl and other members of her family and friends.

Embrey, 18, of Kirtley, Glascote, had admitted 13 charges of making indecent images of children.

Dean Ashton, prosecuting, said when police searched his parents home, in Erdington, in April 2005, they found a computer in his bedroom containing 600 indecent images of children on the hard drive.

He said police also found a number of documents which included a poem describing the indecent assault of a four-year-old girl.

Police carried out a further raid in February 2006 at his aunt's home in Tamworth where he was living and found a iPod which Embrey had used to store 540 indecent images of children.

Mr Ashton said Embrey also kept a diary with "alarming" accounts of meetings with underage girls.

Colin Hart, defending, said although matters found in Embrey's diary were of a most disturbing nature, the line between fantasy and reality could be very wide and that he had never carried out of any of the acts described.